Where to put validation methods GWT according to MVC design

Question

I'm new with GWT and I'm stuck to an issue where to put the validation methods some of them requires asynchronous calls to database my project consists of 2 packages :

client side where the interface and services classes

server side where entities and serviceImpl classes

Do I have to make a third package and place them on it ex: shared ?? or It's Ok to just place them on the client interface classes ex:Login.java

Answer 1

GWT 2.5 comes with support for JSR-303 Bean Validation.

See link: https://developers.google.com/web-toolkit/doc/latest/DevGuideValidation?hl=fr

Answer 2

• It would be great to completely share the validation code in server and client, but run it in both ends.

  As all said ,good things in client side validation :

• Immediate feedback without server visit .

• If client side validation is used, server side validation is still needed